Transseptal systems, devices and methods

Abstract

A transseptal system can include a guidewire, a dilator, and a deflectable sheath configured to safely deliver a puncture needle through a septal wall associated with the fossa ovalis and into a central region of the left atrium of a heart. The dilator can include a dilator nose having a first outer diameter and a dilator beveled segment, extending proximal of the dilator nose, tapering from a second, greater outer diameter to the first outer diameter. The length and interplay of the puncture needle and the dilator nose can be configured such that the puncture needle is inhibited from bending and impinging upon the left side of the atrial septum of the heart during use. A body of the guidewire can include at least one loop segment to provide stable support in the left atrium for delivery of a diagnostic or therapeutic device along its more proximal portions. The deflectable sheath can position and align the dilator nose relative to the fossa ovalis.

What is claimed is: 
     
       1. An anatomical wall crossing system, comprising:
 a dilator extending from a proximal end portion to a distal end portion and including a lumen therethrough, the distal end portion including a dilator nose and a dilator beveled segment, 
 wherein the dilator nose has a first outer diameter and a length of about 5-18 mm, inclusive, 
 wherein the dilator beveled segment extends proximally of the dilator nose and tapers from a second outer diameter, greater than the first outer diameter, to the first outer diameter; 
 a guidewire deliverable within the lumen of the dilator from a guidewire proximal end to a guidewire distal end, the guidewire distal end attached to a puncture needle having a needle body and a needle tip; and 
 a tip sheath positioned around the puncture needle and configured to facilitate coaxial alignment of a needle body axis and a dilator axis; 
 wherein the dilator includes a dilator stop configured to inhibit distal movement of the tip sheath from a position within the lumen of the dilator to a position external to the lumen of the dilator; 
 wherein the tip sheath is configured to expand in diameter upon contact with the dilator stop as it is placed under compression, thereby releasing from the puncture needle. 
 
     
     
       2. The wall crossing system of  claim 1 , wherein the dilator nose includes a cylindrical cross-sectional shape having a wall thickness of about 0.0015-0.005 in, inclusive. 
     
     
       3. The wall crossing system of  claim 2 , wherein the dilator nose is formed from a thin-walled hypotube. 
     
     
       4. The wall crossing system of  claim 1 , wherein the dilator further includes a dilator alignment zone extending proximal of the dilator beveled segment and having a substantially uniform outer diameter. 
     
     
       5. The wall crossing system of  claim 4 , wherein the dilator further includes a dilator waist extending proximal of the dilator alignment zone and having a greater longitudinal flexibility than the dilator alignment zone. 
     
     
       6. The wall crossing system of  claim 5 , wherein the dilator waist has a length of about 5-50 mm, inclusive. 
     
     
       7. The wall crossing system of  claim 5 , wherein the dilator waist has an outer diameter that is 30-90%, inclusive, of an outer diameter of the dilator alignment zone. 
     
     
       8. The wall crossing system of  claim 5 , wherein the dilator waist is formed from a lower durometer polymer than a polymer of the dilator alignment zone. 
     
     
       9. The wall crossing system of  claim 1 , wherein an intermediate portion of the guidewire includes at least one looped segment. 
     
     
       10. The wall crossing system of  claim 1 , wherein the puncture needle has a length of 3-20 mm, inclusive. 
     
     
       11. The wall crossing system of  claim 1 , wherein the needle body has a needle body diameter of 0.001-0.004 in, inclusive, less than the lumen of the dilator to facilitate coaxial alignment of a needle body axis and a dilator axis. 
     
     
       12. The wall crossing system of  claim 1 , wherein the distal end of the guidewire is attached to a proximal end of the puncture needle at a hinge. 
     
     
       13. The wall crossing system of  claim 12 , wherein the hinge includes a shape memory material and, when unconstrained, forms an angle between the distal end of the guidewire and the proximal end of the puncture needle of 45-140 degrees, inclusive. 
     
     
       14. The wall crossing system of  claim 12 , wherein the hinge includes a cylindrical cross-sectional shape having a diameter less than a diameter of the guidewire and of the needle body. 
     
     
       15. The wall crossing system of  claim 12 , wherein the hinge includes a rectangular cross-sectional shape and is configured to bend in a direction defined by a plane of the at least one loop segment. 
     
     
       16. The wall crossing system of  claim 1 , further comprising a deflectable sheath. 
     
     
       17. The wall crossing system of  claim 16 , wherein the proximal end portion of the dilator is configured to engage with an actuator incorporated into a handle of the deflectable sheath, the actuator configured to control distal and proximal advancement of the dilator relative to the deflectable sheath.